The present invention relates generally to medical-surgical cannula devices adapted for insertion through body tissue and the like surrounding an anatomical site in order to provide a conduit for receiving and guiding surgical instruments through such tissue to the anatomical site, thus allowing various medical or surgical procedures to be performed. In particular, the present invention relates to such a cannula device having two selectively separable and interconnectable cannula subassemblies, thereby allowing different surgical set-ups to be achieved, and allowing medical-surgical instruments of different lengths to be received and guided to the anatomical site, without the necessity of removing and reinserting a cannula device during the procedure. The present invention is particularly advantageous in arthroscopic surgical procedures involving small skeletal joints, such as the temporomandibular joint, for example.
In arthroscopic surgical procedures, a cannula is typically used to provide a conduit for introducing various medical-surgical instruments such as powered shavers, hand-operated cutters, arthroscopes, and the like, into the surgical site through the surrounding tissue. The typical cannula is a relatively thin-walled, stainless steel tube, typically having a clamping or coupling device on its outer end. Such a clamping device allows instruments, such as obturators, arthroscopes, etc., to be securely attached to the cannula, with their inner ends protruding from the open inner end of the cannula.
An obturator is inserted through the cannula and locked in place by the clamping or coupling device, with the inner end of the obturator forcibly pushing the surrounding tissue aside as the cannula-obturator assembly is inserted through the body tissue to a position with its inner end adjacent the surgical site. Once the cannula-obturator assembly is properly positioned, the obturator is removed, and the cannula is left in place to provide a clear path or conduit through the body tissue to the surgical site. An arthroscope can then be inserted through the cannula and securely clamped or coupled to its outer end in order to inspect and view the surgical site during the surgical procedure.
Typically, the portions of the instruments that are insertable through the cannula are of a generally standardized length, usually approximately ten centimeters long. Thus, the cannula must also be approximately ten centimeters long in order to function to provide a path or conduit through the body tissue to the surgical site. However, because of the recent development of the use of arthroscopics in small skeletal joints, such as the temporomandibular joint, for example, arthroscopes, shavers, and other instruments necessary in such arthroscopic procedures must be small enough to be used in such small skeletal joints. The reduced size of these instruments (with insertable instrument portions of approximately 5 to 6 centimeters) frequently results in an undesirable reduction in the strength and durability of their components.
In addition, because the above-mentioned standardized length of such instruments portions is frequently much longer than necessary to operate in such small skeletal joints, the extra undesirable length results in the outer open end or portal being inordinately spaced away from the patient's skin. Such unwanted extra spacing from the patient's skin frequently presents difficulties in taping or otherwise securing the cannula to the patient, or in other fixed positions relative to the patient, in order to restrict its movement during surgical procedures.
Because of the above, it has been found that a shorter cannula (typically about 5 centimeters long) would eliminate many of the above-discussed disadvantages in surgical procedures involving the temporomandibular joint or other small skeletal joints by providing the ease and convenience of secure taping or other anchoring of the cannula device, while also allowing for the use of shorter, and thus stronger, shavers, abraders, trimmers, and other surgical instruments. It is deemed highly undesirable, however, to remove a longer cannula required for use with certain obturators, arthroscopes, or other longer instruments, and to reinsert a shorter cannula when the shorter and stronger surgical instruments are required during the same surgical procedure. This is because the removal and reinsertion of a cannula increases the risk of unnecessary trauma or damage to the patient's surrounding body tissue, muscles, and nerves during cannula insertion.
In addition to the above-discussed problems associated with relatively longer or shorter surgical instruments, some surgical procedures require the connection of a source of fluid flow for either introducing a fluid to the surgical site, or for withdrawing fluids from the surgical sites, thus typically requiring additional cannula length for fluid connections, shut-off or control valves, and the like. However, because of the above-mentioned risk of trauma and damage to the surrounding body tissue, muscles, and nerves, it is undesirable to remove and reinsert cannulas of different lengths or configurations when fluid introduction or withdrawal and the use of above-mentioned shorter and stronger surgical instruments are required or deemed desirable in the same surgical procedure.
The present invention seeks to provide a cannula assembly that overcomes the above-discussed problems by allowing the use of fluid introduction or withdrawal apparatus, as well as surgical instruments such as arthroscopes, obturators, powered shavers and abraders, and the like, having instrument portions of different lengths insertable through the cannula assembly, without the necessity of removing and reinserting cannulas of different lengths and configurations during the same surgical procedure.
According to the present invention, an improved surgical cannula assembly adapted for receiving and guiding a surgical instrument having an instrument portion insertable through the cannula assembly includes two selectively interconnectable and separable cannula subassemblies. An elongated, longitudinally outer cannula subassembly is generally hollow and includes open longitudinally inner and outer ends and a fluid port extending generally laterally through a portion of the outer cannula subassembly. The fluid port is in communication with the interior of the generally hollow outer cannula subassembly in order to allow for the introduction or withdrawal of fluids therethrough. An elongated and generally hollow longitudinally inner cannula subassembly includes open longitudinally inner and outer ends, with the open inner end of the inner cannula assembly being adapted to be positioned adjacent a surgical site. A connecting or coupling apparatus is provided for selectively interconnecting the inner and outer cannula subassemblies with one another, with their respective hollow interiors in communication with one another, in order to define a so-called "full-length" cannula. The connecting or coupling means is also selectively separable in order to disconnect the inner cannula subassembly from the outer cannula subassembly, with the inner cannula subassembly defining a so-called "reduced-length" cannula. The connecting or coupling apparatus includes sealing means for sealing the interconnected inner and outer cannula subassemblies in a fluid-tight relationship with one another.
At least one valve is provided and is interconnected with the outer cannula subassembly in fluid communication with the lateral fluid port, with the valve being selectively interconnectable in fluid communication with a source of fluid flow and operable to provide fluid communication through the full-length cannula between the fluid flow source and the surgical site.
Thus the above-mentioned full-length cannula is adapted for receiving and guiding a surgical instrument having a full-length instrument portion insertable through the full-length cannula and for selectively introducing or withdrawing fluids to or from the surgical site. The above-mentioned reduced-length cannula is adapted for receiving and guiding surgical instruments having reduced-length instrument portions insertable therethrough when the insertion of full-length instrument portions and the introduction or withdrawal of fluid from the surgical site is not deemed necessary or desirable, or when it is desirable or necessary to use instruments having stronger reduced-length instrument portions insertable through the reduced-length cannula. Such capabilities are provided by the present invention with only a single insertion of a cannula through the surrounding tissue, muscles, or nerve areas surrounding the surgical site during a given surgical procedure.
Preferably, the above-mentioned valve is interconnected with the outer cannula subassembly for selective rotatable movement of the laterally outwardly-extending valve assembly about the lateral periphery of the outer cannula subassembly to any of a number of laterally outward-extending orientations. During such selective rotatable movement and positioning, the valve is maintained in fluid communication with the fluid port extending laterally through the outer cannula subassembly. In some forms of the present invention, more than one of such valves is provided on the outer cannula subassembly in order to allow for the selective introduction and withdrawal of fluids from the surgical site without the necessity of disconnecting and reconnecting various fluid flow sources. In addition, in such multi-valve embodiments of the present invention, the selective introduction of dissimilar fluids, either simultaneously or at different times, can also be accomplished.